[Bug target/20020] x86_64 - 128 bit structs not targeted to TImode

[gary at intrepid dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20020

--- Comment #21 from Gary Funck <gary at intrepid dot com> 2012-08-12 21:24:40 UTC ---
(In reply to comment #20) 
> X86 doesn't support __int128 and requires SSE for TImode.
> We may need to limit those testcases for int128 target.

OK, I'll add: /* { dg-require-effective-target int128 } */.

> If it is an ABI, we can add a testcase to gcc.target/x86_64/abi
> for x86-64.  If there is no additional issues for x86-64, I think
> we can close it after checking in those testcases.

This issue is performance-related, not ABI-related, per the discussion replies. 

The tests will FAIL on the current compiler because it does not assign TI mode
to 128 bit struct's.  The tests PASS if the suggested MAX_FIXED_MODE_SIZE
definition is added to config/i386/i386.h.

Note: Applying the new MAX_FIXED_MODE_SIZE definition patch will result in at
least one GCC test regression (see comment #9).